The present invention relates generally to a spindle nut holder for a spindle gear for driving levers. More particularly, the present invention relates to a spindle nut holder for a spindle gear for use in extreme operating conditions.
In connection with the use of a spindle gear, simultaneous operations in a vacuum at a temperature near absolute zero and under gamma or x-ray exposure are considered to be extreme operating conditions. The spindle nut holding device for such a spindle gear must also be capable of traverse resolutions in the nanometer range under the above-described extreme operating conditions.
Prior art constructions for spindle nut holders are generally known and can be found, for instance, in lever mechanisms, which are driven by a spindle, for example, in adjustable compasses, in measuring drives or with elevating platforms and screw jacks that have mutually crossing mechanisms (slidable lattice grate). The prior art constructions use trunnion or conic bearings for the rotational axis of the spindle nut. A spindle gear, which must work under extreme operating conditions is described on page 158 in the TESLA Design report 95-01 of the German Electron Synchrotrone DESY (Deutsches Elektronen Synchroton) in Hamburg. In this Design report, FIG. 4.22 shows a forked spindle nut holder with ball bearing trunnions on the spindle nut.
Under the above-mentioned extreme operating conditions, it is a problem that such bearings result in jamming and excessive bearing clearance, which can only be reduced, or at least temporarily avoided, through the presence of costly anti-friction coatings.
It is an object of the invention is to provide a spindle nut holder for a lever-driving spindle gear, which will also function reliably under extreme operating conditions such as in a vacuum, under radiation exposure, and at a temperature close to absolute zero, and which permanently realizes an exact path resolution in the nanometer range.
Pursuant to the invention, this objective is accomplished by providing a spindle nut holder including a spindle nut defining a spindle axis, a frame arranged around the spindle nut and a plurality of strip-shaped links each having an elongated, narrow cross section and first and second ends. The first end of each link is connected to the spindle nut and the second end of each link is connected to a common support frame. The links including a pair of first links and at least one second link. The first links are oriented in a direction perpendicular to the spindle axis and the cross section of the first links provides longer sides and shorter sides. The longer sides of the cross section of the first links are parallel to the spindle axis. The cross section of the second link also provides longer sides and shorter sides. The first links and the second link are arranged relative to one another such that the longer sides of the cross section of the second link are perpendicular to the longer sides of the cross section of the first links. In other words, the cross sectional orientation of the first link is offset from the cross sectional orientation of the second link by 90xc2x0.
An essential advantage of a spindle nut holder for a spindle gear in accordance with the invention is the absence of clearance and friction at bearings for holding the spindle nut at the driven lever. A further advantage of a spindle nut holder in accordance with the invention is the absence of riveted, bolted, clamped, soldered or welded connections at the holder itself, which are normally required for spindle hut holders manufactured from component parts.